A right ventricular conduction delay (RVCD) is an electrical finding, not a disease in itself. It is identified on an electrocardiogram (EKG or ECG) and signifies that the electrical impulse telling your heart muscle to contract is traveling slower than usual through the heart’s right lower chamber, or ventricle. For many, this finding is harmless and does not indicate an underlying heart problem. The significance of an RVCD depends entirely on the context of an individual’s overall health, symptoms, and any other medical conditions.
The Heart’s Electrical System and Conduction Delays
The heart’s consistent rhythm is orchestrated by a specialized electrical conduction system. This process begins at the sinoatrial (SA) node, the heart’s natural pacemaker. The impulse spreads across the atria, causing them to contract, and then converges at the atrioventricular (AV) node. From the AV node, the signal travels down the bundle of His, which splits into the right and left bundle branches that carry the electrical signal to the ventricles, triggering a coordinated contraction.
A right ventricular conduction delay occurs when signal transmission through the right bundle branch is slowed. This does not mean the signal is completely blocked, but that it takes longer to travel this pathway. As a result, the right ventricle contracts slightly later than the left ventricle, which produces the characteristic changes on an EKG.
This finding is often used interchangeably with incomplete right bundle branch block (IRBBB). The distinction lies in the degree of the delay. In a complete right bundle branch block, the signal is entirely obstructed, forcing it to take a much slower detour through the heart muscle to activate the right ventricle, resulting in more pronounced EKG changes.
Identifying the Causes of a Right Ventricular Delay
Normal Variant
An RVCD is frequently a normal variant seen in healthy, asymptomatic individuals, particularly children, young adults, and athletes. In these cases, the finding is considered benign. It reflects a minor deviation in the heart’s electrical wiring that does not impact heart function.
Structural Heart Changes
Structural changes to the heart can also lead to a right ventricular delay. Conditions that cause the right side of the heart to enlarge or work harder can stretch or pressure the right bundle branch, impeding its ability to conduct electricity. An atrial septal defect, a hole between the heart’s upper chambers, can cause this by allowing extra blood to flow into the right side of the heart. Another cause is right ventricular hypertrophy, a thickening of the right ventricular muscle often due to high blood pressure in the lungs.
Lung Conditions
Issues originating in the lungs can impact the right side of the heart and its electrical system. Because the right ventricle pumps blood into the lungs, any condition that increases resistance in the pulmonary arteries can cause strain. Chronic lung diseases like chronic obstructive pulmonary disease (COPD) or a pulmonary embolism, a sudden blockage in a lung artery, can lead to increased pressure in the right ventricle that manifests as a conduction delay.
Other Factors
Other less common factors can contribute to an RVCD. Electrolyte imbalances, particularly high levels of potassium (hyperkalemia), can interfere with the heart’s electrical signaling. Certain medications that affect the heart’s sodium channels may also slow conduction. In rare instances, an RVCD can be an early sign of a more progressive conduction system disease or an inherited condition like Brugada syndrome.
Diagnosis and Clinical Significance
A right ventricular conduction delay is diagnosed using an electrocardiogram. The diagnosis is made by observing specific features in the EKG waveform, specifically a QRS duration between 110 and 119 milliseconds. This measurement reflects the time it takes for the electrical impulse to travel through the ventricles. The signature pattern is an “RSR'” configuration, sometimes described as “rabbit ears,” in the EKG leads over the right side of the chest (V1 and V2).
The clinical significance of this finding is highly dependent on the individual’s circumstances. In an otherwise healthy person with no symptoms, an isolated RVCD is considered a benign finding that requires no further action. The electrical delay is minor and does not affect the heart’s ability to pump blood effectively.
However, when an RVCD is a new finding, or if it is discovered in a person experiencing symptoms such as shortness of breath, chest pain, or fainting, it signals the need for further evaluation. In this context, the delay may be a clue to an underlying structural or functional problem. The next step is often an echocardiogram, an ultrasound of the heart, to check for abnormalities like an atrial septal defect or right ventricular enlargement.
Management and Outlook
The management of a right ventricular conduction delay is focused on addressing any underlying cause, rather than the EKG finding itself. If a thorough evaluation reveals no associated heart or lung disease, and the individual is free of symptoms, the RVCD is considered a normal variant. In this situation, no specific treatment is necessary, and a physician may simply note the finding in the patient’s medical record.
When an underlying condition is identified as the cause of the delay, the treatment plan targets that specific issue. For example, if an atrial septal defect is found to be causing significant strain on the right heart, a procedure to close the defect might be recommended. If the delay is linked to pulmonary hypertension, medications will be prescribed to lower the pressure in the lung arteries. By treating the root problem, the strain on the right ventricle can be reduced.
The long-term outlook for an individual with an RVCD is excellent when it is an isolated finding in a healthy heart. It does not progress to a more serious heart block or cause adverse health outcomes. For individuals where the delay is a symptom of another condition, the prognosis is tied to the severity and manageability of that underlying disease. The RVCD serves as a useful marker that prompts a deeper look into the heart and lungs.